Method of hot-rolling extremely thin steel sheets



W. E. HANNA. METHOD OF HOT ROLLING EXTREMELY THTN STEEL SHEETS. APPLICATION FILED mac. 6. 1920.

EAQGJ? 8Q. Patemm Aug. 22, 1922 MIT/E/VTQI? W TNESSES UNITED STATES Parent entice.

WILLIAM E. HANNA, OF BRACKENRIDGE, PENNSYLVANIA, ASSIGNOR TO VALLEY HOLDING CORPORATION, OF BRACKENRIDGE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

METHOD OF HOT-BOILING EXTREMELY THIN STEEL SHEETS.

Specification of Letters Patent.

Patented Aug. 22, reveal Application filed December 6, 1920. Serial No. 428,487.

T 0 all whom it may concern:

Be it known that I, WILLIAM E. HANNA, a citizen of the United States, and a resident of Brackenridge, in the county of Allegheny and State of Pennsylvania, have made a new and useful Invention in Method of Hot- Rolling Extremely Thin Steel Sheets, of which the following is a specification.

This invention relates to the manufacture of steel sheets of extreme thinness.

In U. S. Letters Patent No. 1,340,149, issued to Vere B. Browne on May 18, 1920, there is disclosed a method of manufacturing sheets of extreme thinness, of which this method is'an improvement.

In experimenting with the method disclosed in said patent, I discovered that I can materially increase the output thereunder, especially in the production of silicon steel sheets of extreme thinness.

I discovered that instead of placing relatively thin sheets of silicon steel singly be tween the heavier sheets or bars of dissimilar steel as outlined in said patent, I can group two, three or four of such relatively thin sheets of silicon steel together between heavier sheets or bars of dissimilar steel raised to rolling temperature, and after the thin sheets are reduced to the required degree of thinness or gage, can then open up the pack.

The single sheet of drawings forming a part of this application diagrammatically illustrates a pack built with this invention.

I find that all of the relatively thin sheets of such a group absorb suiiicient heat for rolling and do not weld one to the other nor 1 to the relatively heavy sheets between which the group is rolled down. The thin sheets, I find, do not weld one to the other, because the temperature thereof is too low to efiect welding and the outside sheets of the group do not weld to the relatively heavy sheets or bars because of the dissimilarity in the met-' als; the mild steel flows more rapidly 0r readily than the silicon steel thus preventing welding.

The temperature absorbed by the silicon steel sheets is sufiicient, since these must be rolled at a low temperature on account of their silicon content. The heavy outside sheets of the pack protect the silicon steel up in accordance sheets during the rolling. I find that if I group more than four silicon steel sheets together, they have a tendency to wrinkle or fold and I have found that in commercial practice, a group of four such sheets is the limit to which I can go. i

In carrying out this method, I preferably take two sheets of silicon steel rolled to 29 gage (.014 of an inch), give to each of these a charcoal wash, then place or group them together between two pickled bars or relatively heavy sheets of mild or soft steel, raised to low rolling temperature, corresponding to a dark color.. The pack thus made up is then rolled tofrom 72 to 78 inches in length, opened up and each of the silicon steel sheets is then cut into two pieces. These are given another charcoal wash and new packs assembled, each of which consists of three sheets of silicon steel grouped together and inserted between other pickled bars or heavy sheets of mild or soft steel, raised to=a low rolling temperature. The packs are then rolled to such ll ngth as will bring the silicon steel sheets down to the desired gage or thickness, .002 or .003 of an inch as is required.

I find that the packs may be readily opened and that the silicon steel sheets when thus rolled will not weld or stick one to the other, nor to the relatively heavy sheets of mild steel.

I claim is 1. The method which consists in grouping two silicon steel sheets while cold, in placing such group between pickled bars of mild steel raised to rolling temperature,-in rolling Having thus described my invention, what the pack thus made up to 72 inches or more in length, in separating the pack, cutting each ot the silicon steel sheets into two pieces, re-grouping two or more of these cut sheets together and inserting such group between pickled bars or relatively heavy sheets of mild steel, raised to rolling temperature rolling the pack to such length its Will give the desired thickness to the silicon steel sheets. 10

In testimony whereof, I have hereunto subscribed my name this 2nd day of December, 1920.

' WILLIAM E. HANNA. 

